Effect of combined misonidazole and accelerated neon ions on a human melanoma transplanted into nude mice.
The response to accelerated neon ions of human Nall melanomas growing in nude mice was measured by an in vitro colony-forming assay following in situ tumor irradiation in the midposition of a 10-cm extended-peak ionization region. Values of the relative biological effectiveness (RBE) for peak neon ions compared with 60Co gamma radiation were 3.2 and 3.4, respectively, at the 1% and 10% survival levels. Following irradiation with peak neon ions, the repair of potentially lethal damage (PLD) was comparable to that observed after gamma irradiation. When misonidazole (1 mg/g intraperitoneal dose) was administered in combination with extended-peak neon ions, the drug enhancement ratio (ER) at the 1% survival level was 1.5 if the tumors were removed and plated in vitro immediately following irradiation, and 1.9 if tumor excision and plating were delayed for greater than 6 hours. Administration of misonidazole completely inhibited PLD repair following either gamma irradiation or extended-peak neon-ion irradiation.
D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003114:Colony-Forming Units Assay; D005260:Female; D008297:Male; D008545:Melanoma / Q000628:therapy*; D051379:Mice; D008819:Mice, Nude; D008920:Misonidazole / Q000008:administration & dosage*; D009356:Neon / Q000627:therapeutic use*; D009368:Neoplasm Transplantation; D009593:Nitroimidazoles / Q000008:administration & dosage*; D011882:Radiotherapy, High-Energy; D012878:Skin Neoplasms / Q000628:therapy*
D009593:Nitroimidazoles; D009356:Neon; D008920:Misonidazole